Process and apparatus for separating material



3 Sheets-Sheet l Fil ed Feb. 2, 1942 June 6, 1944.

' 'INVENTOR.

' rjsss'MMc'Ge BY J. M. MGGIEE June 6,

PROCESS AND APPARATUS FOR SEPARATING MATERIAL Filed Feb. 2, 1942 s SheetS Sheet 2 INVENTOR.

rfsse JV. Z'fc Gee June 6, 1944. J M, MCGEE 2,350,625

PROCESS APPARATUS FOR SEPARATING MATERIAL INVENTOR. 176566, M MC Gee Patented June 6, 1944 PROCESS AND APPARATUS FOR SEPARATING MATERIAL Jesse M; McGee, Oak Park, Ill., assignor to, Roberts and Schaefer Company, Chicago, I l l a corporation of Illinois Application February 2, 1942. Serial o. 429,142

4 Claims.

This invention relates to the art of separating materials; and is particularly concerned with a new 'orgam aoon'and coaction of apparatus forseparatin'g comminuted material in accordance' with the specific gravitie's and the sizes 5 havingaparticleisize varying. approximatelyirom or" its particles. The new organization and com- A" to 0?. Practical. tests reveal thatjfinely bination of appartus and the mode of operation divided. matter ofa. particle. size. smaller than. thereof result in a novel process whereby the about 48. mesh contained in the .raw,.coa1. is comminuted matter can be separated more ecoresponsible. for. certain difiicultieswhich. appear nomically and more efiicie'ntly than was hereto- 0 when it. is attempted to. clean such. material. fore possible. The, inventiondescribed.. below attempts. a The invention is particularly adapted to and solution of. the. problem. by attacking the. causes will be described herein in connection with the of. the difficulties. It. removes from, the raw. yng or separation of material such as feed the dust-like constituents of a size less. raw coalyh'aving a particle size varying from than approximatelia 48. mesh and. subjects. the about A" to 0" in diameter, that is, material remainder. of. the. feed, to a. separation treat: containing a relatively large amount of finely mentin. an. airacleaner. employinga closed; an: divided and dust-like particles. circuit. which. connects the. air .cleanerwith ap,-; The raw material' is fed to a mechanical sepaparatus. for collecting and concentrating. the rator'whichremoves dustlike matter therefrom 2o residual. and. tlregattrition dust. It is belieyed and the remaining coarser material is supplied thatuthisis. thefirst, instance showinga syste n through an exteriorl'y closed conduit to a secand. process, which, employs machinery ot the 0nd air-controlled separator, e. g., of the type type. and in, the. combination and cgajggtiot asdisclosed in the U. S. Patent No. 2,245,942, issued disclosed herein; V Junel7, 1941, wherein the material is separated The basic, organization. i lus ated in. 3 g}. in accordance with the specific gravities of its comprisesthe f e e d ,bi n Ll irom whichthe raw particles. Exhausfiair'from the second sepafeedof, coalhay' -g particl e s of a diameter. of. rator is circulated in a closed. system for reuse AftoO" isjed;by suitalqlemeans for example, therein and dust-like matter is removed from a conveyor lg to the ;me chanica lseparator I 3 the circulating air stream. A bleeder connec- This separat qr may he of the general typedis;

tion is provided between the supply conduitv from the first separator and the exhaust from the second separator for thepurpose of maintaining the circulating air stream. substantially uniform. The temperature. o fvthe air stream circulating throughthe air-controlled separator is by this arrangement kept substantially constant. n I I g j: The abcveintimatedobjects and features will bebrou gihtfoutinfthe course of the detailed description which is rendered below with rel'erence to the accompanying drawings. In these drawmes,

r Fig. 1 shows a diagrammatic flow sheet representing embodiment. ofcthe invention in a basic jai' ds'iniple. organization or apparatus;

Figs. 2 and 3, when joined at the horizontal connecting lines, illustrate in a diagrammatic manner 'asubstanti'allyf complete cleaning and separating plant embodying the invention; and

Fig. "4is an elevational view showing an em bodiment of the structural arrangement and interconnection of the apparatus.

uremia-are numbered alike throughout the drawings use in "the" bi s; illustrated n Figs.

(01. zos s qz 2 and 3. Details and elements which are well. known will be described. only. to the extent. nee: essary for understanding; the. invention.

It is assumed. that'it is desired'toclea-n. coalc o ed. Pa eQi NQ- .7mm daiesiD: amber 2 .9. 91. hef akeo :c mpl teness hi eparator s. riefl am ss 99 lQW-.-

' tbrmsri es n ter. at he- 91 and is; in this specific; embodiment particles of a me ee r isp ali m.

ite; l s l he i he" mecham bi l mil a sit. as: 3; r ina-nitrite ,..ai.d. r. herrow 5-" a h air impulses go through the perforate deck and through the layer of material thereon, which moves along the deck, keeping the material bed mobile and causing stratification of its constituent parts in accordance with the 'spe-' cific gravities thereof. The clean coal is discharged at the opposite end of the cleaner, as' indicated by the arrow I8. 1 The refuse, that is, particles of heaviest specific "gravities; is discharged as indicated by the arrow'l9. Middlings consisting of particles of intermediate specific gravities .may be discharged as indicated by the arrow 20. The'above noted patent may be consulted for further details concerning the structure and operation of the air cleaner.

The air cleaner is also provided with a dust hood 2| which conducts the dust-laden air through a conduit 22 provided with a suitable valve 23 to a primary collector 2.4. The valve 23 may be part of the intake conduit of tlie collector.

This collector may be of the type described in U. S. Patent No. 1,985,947, dated January 1, 1935. Its shape, asindicated in the-drawings, is exteriorly somewhat similar to that-of-the mechanical separator 13. The internal mechanism,

Air impulses are injected inter. the air chamber by means of a fan l.'|;iI1.The.

tially clean air, free of dust particles, escapes however, is different. The collector is provided in its upper part with-a cylindrical interi'orly downwardly depending extension forming in the upper'cylindrical portion an annular channel. The dust-laden air from the conduit 22 is injected into the concentrator tangentially so as to create a rotating air stream which gyrates downwardly along the inner walls-of the collector.- The eficiency of the collector is a function of the inlet velocity and the fineness and character of the particles to be separated irom'the dust-laden air coming from the air cleaner l6, and it will be apparent thatthe inlet velocity can be effectively regulated by properly positioning the inlet valve 23.- The entering dustladen air'stream is directed tangentially along theinner' surface of the outer wall of the collector so that the maximum whirling or centrifug'al effect will be imparted to thesuspended material. The suspended material is depositedor 4 and 45. The remaining material of coarser parconcentrated adjacent the inner closed walls of the collector housing due to the centrifugal force impartedby the whirling air? The smaller lower end of the housing may be equipped with an extension having an upwardly projected conical bottom in the interior thereof, as described in detail in the previously mentioned patent, and is provided with an outlet leading substantially tangentially from one side of the housing to connect withthe outlet conduit indicated in Fig. 1 at 25.

- A relatively small proportionof'the' air strearn introduced into the collector is withdrawn throughthe conduit 25,'thus producing a sumcient down draft adjacent the inner 'walls of the concentration of the suspended material. The vortex of the rotating air currents within the collector 24 is broken at the bottom thereof by a centrally positioned conical member. Therefore there is in this collector a rotating marginally whirling and downwardly gyrating air current which deposits the suspended material and discharges it downwardly through the extension 25, together with a small amount of air.

The greater part of the air, which is substanthrough a pipe in the upper part of the collector into the conduit 26 leading back to the fan H for injection into the air cleaner Hi. There is thus a closed air circuit established between the air cleaner I6 and the dust residue-collecting apparatus comprising the collector 24. The small amount of air withdrawn through the discharge pipe 25 may be replaced in the closed air circuit by a bleeder connection between the conduit M and the conduit 22' indicated by the line marked by numeral Iii. Whatever amount of air is withdrawn at 25 will therefore be automatically replaced at 22 from the conduit 14.

The collector 24 discharges through the conduit 25 into the concentrator 21. This concentrator may be of the same general structure as the collector 24 except that substantially no air is withdrawn at the outlet 28. The air from the concentrator 2'! is vented to the outside by the fan 30 through a pipe 29, and the concentrated residual and attrition dust is removed through the outlet 28 by means of a suitable valve, 2. con-.

veyor, or a gate.

Referring now to Figs. 2 and 3, which show, a complete plant embodying the invention, nu; meral 3| indicates the'supply of raw coal Whichistransported by means of asuitable'conveyon along the dot-dash line 32 to an elevator 33.; The conveyor 32 operates through the medium of j the drive means 34, 35 and 36. The elevator 33.; operates through the medium of the drive means 3'! and 38. The raw coal, which may be composedg of particles having a diameter, as previously; stated, of approximately to 0", is elevated; for discharge onto a raw coal conveyor diagram-. matically illustrated in Fig. 3 at 39. This con-- veyor distributes the raw coal to the supply or surge bins 40 and 4|, the first bin feeding the raw material to the mechanical separator 42 and the second bin feeding the raw coal to the mechanical separator 43. Each of these mechanical separators corresponds in structure and function to the separator l3 described in connection with Fig. 1. The separators 42 and 43 remove the fines of a particle size smaller than 43'mesh from the raw, feed and discharge these fines at 44 ticle size x 48 mesh) is discharged from the separators at 46 and 41, and is fed to the air cleaners 48 and 45. Each of these air cleaners may be of the same general type and structure as the air cleaner l6 described in connection with the basic system shown in Fig. 1, each air cleaner being provided with a dust hood, as shown at '50 and 5|. The dust-laden air (containing the residual and attrition dust separated out housing to s'ucKdOWn the air carrying the greater 7 from the material inthe air cleaners) is withdrawn from the dust hoods through the doubledash line conduits 52 and 53 leading to the collectors 54 and 55. Each of these collectors may be of substantially the same structure and may have the same operation'as the collector 24 de-.

pribedin.@eheeiismflihii shasiqsxihezshqiy M in Fig. 1. Y

h o' senla r rex li gq t t ii qei tianajisj hrough the conduits 56 and 51 shown j 3 iliesas eiihabesiq is emehew in. Fi 1, we have here aga iri aprelirninary separation of do not wa'fra t.

5 19m fi see ifi s. e .a reeir u l dlseexit se aratio 45 5: t bas e s uire le, harm. 2 9s w and 55.

F Pi l y Part of the dust from the dust convyorll nlay r and as ig: 2); These screens divide theclean coa into suitable; sizes; Theuiiderj-size fro'rnfall the iscreefisfhiay'he,foifl'exarrip lef g $48 niesh iana may'bedischarged along "the r e jss; The .ever-shelfr pmahese sreens; 'forijexar'nple, the particle sizes from to r", "may 'bei'disfgchai'ged along the line ,81; The sized coallrr'iay" thenbe conducted to theloading boorn or con- ,veyor90, and may thenb'e loaded int'orailroad V fcjarsiindicated at 94. Partf'of the sized coal' 'may v be conducted to' the compartments 9! and 191 and fromlthere, if desired, to the conveylor 93 forsuitabl disposal or storage The :middlings from the air cleaners 8 and ,49 (Fig. 3) maybe dischar ed 'at, 95 96 aind 91:98, respectively. Depending on the quality ,of, these middlings, it'mayjbedecide'd to recirculatethem and in this case they are condiicted to, a refu e. n lml dql s on e r wh transports thein Qto the rniddlings eleyator 1B0,

titre-Wit r w iq ni ifillb conduits l l and may bewholl'y', cr -man "added toth'e' clean coal, or may he re-circulated together ,with thermiddlings, or disch""ged'as frffise; alrqependiiigibrrtheir-euantw'and cal fbeld'fi'ging tofine supporting" s'tructiire brto "the housing" SlidS 5f the" ifla'fit aire ilidibatd bllt 'a'l''fiot mafkd in fil'i drawings. FigFQ'SFlCSWS the equipment diagrammatically illustratedhn the 'leftfhalf of Fig. 3," namely; theairfcleamr Q48, dust hood andcor'id'uit *521e'a'ding to""the "collector 54 with the discharge pipe BBret'urning I the clean air from thej collector to the air'clean'er by way of afsu'iftahly an /eni ma: The'col- 1ector"'54 discharges dust-"like material together with anamountfof "air through thecohduitt!) into the cohcentrator 62"a'nd the"latter discharges the dust substantially without any' 'air through suitable; gate or" valve provisions onto the'idust conveyor 10. The lattef may'jglis- -charge either onto the clean coalfconveyor IT'or "onto the middlings' conveyor f 99. The refuse conveyor I02 receives the materiahto beidiscarded from the discharge spout of the air flow "cleaner 48. "fThejmiddli'ngs may be discharged "with'or without the fines from the mechanical separator 42 through the connection I53. The air from the concentrator 62 "is ventedto'the outside by meansof' the pipe 64 through the medium of the fan 65; Numeral 40 indicates the surge'bin or supply bin for the mechanical separator 42 which receives its supply froin the"con- "vey'or 39 over afchute leading downwardly from the elevator 33. The latter "picks up the raw "material for separation andcleaning from'the conveyor '32, fall as previously described. Suitable gate means may be used withinior in place ""If he' invention disclosed "herein" thus provides ew featursf 'which may be briefly surni'ned up allows:

' Al Fines within a definite size rang that may cause: difiiculties' in orthodox cleaning methods )I are "substantially I wholly removed prior to subjectin'g the raw material to the gravity separat i onprocess. This removal is not feasihle 'with apparatus customarily ernployed in theart. The

new organization of devices} including prelim- Qinary treatment of the raw material in thelrne "chanical separator} as disclosed herein, makes such substantially complete and controlled prelimina'i'yreinoval of fines of a definite 's iz'eiange possible and does so in an eflicient manner. I'Ihe advantages resulting therefrom are:

" 1 "Ihe efiective operating {capacity of a the t e let r.ele atin ihema eti l' dJ-i-e ai y s arat r, $1 beaii aih ji e reduced.

terial fed into it is not loaded with burdensome fines but is restricted to particle sizes which yiel to stratification without hampering it;

2. The operation'of the gravity separator'is rendered more efficient and more economical because the relative absence of "fines avoids a series of complications which would otherwise occur; 7 V

3. The speed of effective gravity separation is increased; and f 4. The ash content of the clean ;coal is B. The residual dust which may be contained in the raw feed supplied'to 'the'gravity separator from the mechanicalseparator, or may be produced by attrition incident to the gravity separation, is positively collected and efficiently concentrated by means of dust-collecting devices connected with the gravity separator in a'manher which substantially eliminates the trouble some dust-collecting problem inherent in'prior cleaning systems of this class.

C. The air-controlled gravity separator is :supplied with air in a closed circuit drawing on .air from the apparatus and returning it, again for use, thereby producing the following advan- 'tages:

1. The temperature of circulating air current is kept substantially constant; it is approximated to the temperature of the material to be cleaned, facilitating the stratification process; and

2. The circulating air temperature may rise slightly above the temperature of the material, thus supporting the expulsion of residual and attrition dust from the material bed in the air cleaner.

D. The provisions for circulating the air through the gravity separator in a closed circuit are combined with the dust-collecting and dustconcentrating means, furnishing a completely unitary structure.

The above summary is furnished in order to emphasize the most prominent features of the invention. Other features appear from the previously rendered detailed description.

Changes may be made within the scope and spirit of the appended claims in which I have defined what I believe to be new and desire to have protected by Letters Patent of the United States.

I claim:

1. In combination, an air-controlled gravity separator of the class described, a tubular exteriorly closed conduit for supplying material together with an amount of air to said separator :for treatment therein, a closed system for continuously circulating air under pressure through said separator and through the material therein,

means in said system for continuously removing from said air simultaneously all dust-like matter extracted from the material treated in said separator and for separately collecting and} discharging said collected dust-like mattertogether with a relatively small amount of air, and bleeder matter comprising, in combination, a mechanical separator for receiving said raw coal for prelimiirom, a separate air controlled gravity separator,

' means forming an exteriorly closed tubular supply conduit connecting said mechanical separator and said air controlled separator for conducting to the latter together with an amount of air only the coarser raw material having a particle size of about 14" to 46 mesh discharged from said mechanical separator alter elimination of the bulk of said smaller particles, a fan for supplying air currents to said gravity separator to enect separation therein 01' said coarser raw material in accordance with the specific gravities or the particles thereof, an exhaust conduit for withdrawing from said gravity separator air used in said gravity separation together with residual dust-like particles contained in the coarser raw material treated therein and produced therein by attrition incident to the separation treatment, a device for mechanically treating all said withdrawn dust-containing air to remove therefrom substantially all of the residual and attritionproduced dust-like particles contained therein, a tubular outlet through which the cleaned air is expelled from said device, means forming a tubular uninterrupted return conduit which is closed to the outside throughout for conducting all or said cleaned air from said outlet directly and solely to said fan for re-use in said gravity separator, a concentrator for receiving from said device together with a small amount of air the dustlike matter removed from the air withdrawn from said gravity separatorand for precipitating said separator for receiving comminuted intermixed raw material to remove therefrom the bulk of dust-like particles contained therein, a second air-controlled separator for receiving the material freed of such dust-like particles to effect separation thereof in accordance with the specific :gravities of its component parts, an exteriorly closed supply conduit for feeding the material from said first to said secondseparator together Y with an amount of air, a dust collector for receiving the exhaust air from said air-controlled separatorto clean said air of dust-like particles temperature of the air stream circulating;

through said separator is kept substantially constant independent of outside temperature conditions. 7

2. Apparatus for the dry cleaing of raw coal containing an appreciable amount of dust-like conduit for bleeding air from said exteriorly 'closed supply conduit into said exteriorly closed exhaust conduit tocompensat'e for air lost in said dust collector, whereby the amount of clean air conducted to said air-controlled separator by means of said exteriorly closed conduit is main- ;tained substantially uniform and the tempera- V ture thereof is keptsubstantially constant rehaving a maximum particle size of about /1 and;

'gardles's of outside temperature conditions.

4. The process of separating comminuted intermixed raw material comprising the steps of feeding such material together with an amount of air to an air-controlled separator, confining said feed to exclude therefrom ingress of outside air, exhausting spent air from said air-controlled separator, confining said exhaust to exclude therefrom ingress of outside air, cleaning said exhaust air of dust-like matter, venting to the outside part of said cleaned exhaust air, returning the remaining cleaned air to said air-controlled separator for re-use therein, confining nerature conditions.

JESSE M. McGEE. 

